当cabal install testpack-2.1.1失败时,以下错误消息意味着什么:
... Everything above this succeeded with no problems.
[22 of 22] Compiling Control.Monad.Cont ( Control/Monad/Cont.hs, dist/build/Control/Monad/Cont.o )
Registering mtl-2.2.1...
Installing library in /home/ely/.cabal/lib/mtl-2.2.1/ghc-7.4.2
Registering m